So, for dash they could have put pauses on both sides, maybe?
Few examples:
a) -·· => Tak. Tak, tak.
b) ··- => Tak,tak. Tak.

Then only option that wouldn't work is -·-.

Other option, that would allow all combinations, is if they devised solution where dash and dot knocks used different surfaces to produce different sound. E.g. for dash on a wall and for dot on wod (like a bed frame).